[KConfig] Add RT_USING_NETUTILS configuration for network.

components/net/KConfig

@@ -1,6 +1,6 @@
 menu "Network stack"
 
-menu "light weight TCP/IP stack"
+menu "Light weight TCP/IP stack"
 config RT_USING_LWIP
     bool "Enable lwIP stack"
     default n
@@ -169,4 +169,8 @@ endmenu
 
 source "$RTT_DIR/components/net/freemodbus/KConfig"
 
+config RT_USING_NETUTILS
+    bool "Enable net utils"
+    default n
+
 endmenu